Thank you Notorious for the lengthy summary of MoP (subjective ofc), you have sold me on giving it a try. I have played on Retail from late Vanilla to late Cata (LFR and the monotony of Dragon Soul was the deal breaker for me) and eventually got burnt out and quit, only to play on Private Servers (tried them all on every expansion from Vanilla - Cata) such as Molten with friends occasionally for nostalgia sake. There have been several things that WoW improved on from Vanilla and several things that went down the drain as well over the years. Reduced gearing disparities, Catch-Up mechanisms, Transmog, Reforging, Complexity in Gameplay etc. are the things that I felt were great introductions to the game. On the other hand I miss the the sense of community through guilds, difficulty of 5-man Heroics and unique dungeon designs, unique class designs (less homogenization), world PvP and leveling. Things like Talent trees, Class Balance etc. never bothered me much because I know one way or the other they will get it as close to right as possible by the last patch of the expansion (and that is the best thing about Private Servers). Overall the only things that bothered me the most and that I feel were bad additions to the game were :
1. Flying
2. Reduced Heroic 5-man difficulty (AoE fest and less use of CC)
3. LFD
4. LFR
5. Allowing PvE gears in PvP
6. Homogenization of classes (now this is a tough one as it is hard to increase Class Complexity without increasing Homogenization, so this is alright I guess)
Seeing as you have also mentioned these 'problems' as well puts us on the same wavelength and makes me trust your judgement. Now most of my friends have moved on from WoW, so I would like to finally give MoP a try (I have no problem with bugs on Private servers, as I'm used to them) as I've only heard great things about it for some time now. I love the Asian theme of Pandaria as I feel it is a nice break from the typical Human vs Orc theme of Warcraft (I understand that is never going away). So thanks for giving me the last push to jump into the Mists!